Looks like the checks internally on Xojo string are incorrect somewhere
For those that know the internals of Xojo string then nil Xojo string is always zero length and is valid string.
Not sending this as bug report since it is not really something that can be reproduced as it just came randomly after long run.
But I am sure they could look for the error message and see what the check is doing.
And I got it reproduced now:
Clipboard setting RawData to empty string on Windows crashes with hard crash in IDE, and in compiled app it hard crashes and says that a length cannot be obtained from a nil string.
https://tracker.xojo.com/xojoinc/xojo/-/issues/79435
Code to reproduce it:
var c as Clipboard = new Clipboard
c.RawData("private.idoc.summary") = ""
Run it on Windows, and you get hard crash because of assigning empty string.
Can confirm this does not happen on Mac (Intel).